Analog Integrated Circuits and Signal Processing

, Volume 82, Issue 2, pp 423–430 | Cite as

A variable-gain superregenerative amplifier controlled by duty-cycle for signal conditioning

  • Fernando Rangel de Sousa
  • Roddy Alexander Romero Antayhua
Article

Abstract

In this paper, a variable-gain amplifier (VGA) adjusted by the duty-cycle of a control signal is presented. This circuit is based on the superregenerative concept created by Armstrong back in the 1920s. The technique selected allows a fine control of the gain to be performed without any D/A converter at the interface between the digital control and the amplifier, as generally seen in other VGAs. An integrated-circuit version of the VGA was fabricated in a standard \(180\,{\mathrm {nm}}\) CMOS process, aimed at achieving low-power consumption. Simulation results show a maximum gain of \(45\,{\mathrm {dB}}\) within a \(900\,{\mathrm {mV}}\) linear range, \(0.5\,\%\) THD and a power consumption of \(6.4\,\upmu {\mathrm {W}}\). Measurements on the chip were performed and the results corroborate the simulations.

Keywords

Signal conditioning Superregenerative amplifier Variable gain amplifier Analog design 

References

  1. 1.
    De Boeck, J. (2011). Game-changing opportunities for wireless personal healthcare and lifestyle. IEEE International Solid-State Circuits Conference Digest of Technical Papers pp. 15–21.Google Scholar
  2. 2.
    Wang, Changhong., Wang, Qiang., Shij, Shunzhong., & Sousa, F.R. (2012). A distributed wireless body area network for medical supervision. In Proceedings of the IEEE Instrumentation and Measurement Conference (pp. 2612–2616). Graz, Austria.Google Scholar
  3. 3.
    Yoo, J., Yan, L., Lee, S., Kim, H., & Yoo, H. (2009). A wearable ECG acquisition system with compact planar-fashionable circuit board-based shirt. IEEE Transactions on Information Technology in Biomedicine, 13(6), 897–902.CrossRefGoogle Scholar
  4. 4.
    Ng, K. A., & Chan, P. K. (2005). A CMOS analog front-end IC for portable EEG/ECG monitoring applications. IEEE Transactions on Circuits and Systems I: Regular Papers, 52(11), 2335–2347.CrossRefGoogle Scholar
  5. 5.
    Catunda, S. Y. C., Naviner, J.-F., Deep, G. S., & Freire, R. C. S. (2003). Designing a programmable analog signal conditioning circuit without loss of measurement range. IEEE Transactions on Instrumentation and Measurement, 52(5), 1482–1487.CrossRefGoogle Scholar
  6. 6.
    Romero, R.A., Silva, G.M., & Sousa, F.R. (2012). A duty-cycle controlled variable-gain instrumentation amplifier applied for two-electrode ECG measurement. In Proceedings of the IEEE Instrumentation and Measurement Conference (pp. 1270–1274). Graz, Austria.Google Scholar
  7. 7.
    Thoppay, P. E., et al. (2011). A 0.24-nJ/bit super-regenerative pulsed UWB receiver in 0.18-μm CMOS. IEEE Journal of Solid-State Circuits, 46(11), 2623–2634.CrossRefGoogle Scholar
  8. 8.
    Armstrong, E. H., et al. (1922). Some recent developments of regenerative circuits. Proceedings of the Institute of Radio Engineers, 10, 244–260.Google Scholar
  9. 9.
    Pala-Schonwalder, P., et al. (2009). Baseband superregenerative amplification. IEEE Transactions on Circuits and Systems I: Regular Papers, 25(9), 1930–1937.CrossRefMathSciNetGoogle Scholar
  10. 10.
    Figueiredo, A.P., Catunda, S.Y.C., & Sousa, F.R. (2013). Uncertainty analysis of a superregenerative pulse-width programmable gain amplifier. In Proceedings of the IEEE Instrumentation and Measurement Conference (pp. 306–309). Minneapolis, USA.Google Scholar
  11. 11.
    Li, D., & Tsividis, Y. (2000). Active LC Filters on silicon. IEE Proceedings—Circuits, Devices and Systems, 147(1), 49–56.CrossRefGoogle Scholar
  12. 12.
    Enz, C., & Temes, G. (1996). Circuit techniques for reducing the effects of op-amp imperfections: autozeroing, correlated double sampling, and chopper stabilization. Proceedings of the IEEE, 84(11), 1584–1614.CrossRefGoogle Scholar
  13. 13.
    Zou, X. (2009). A 1-V 450-nW fully integrated programmable biomedical sensor interface chip. IEEE Journal of Solid-State Circuits, 44(4), 1067–1077.CrossRefGoogle Scholar
  14. 14.
    Yan, L. (2010). A 0.5-μVrms 12-μW wirelessly powered patch-type healthcare sensor for wearable body. IEEE Journal of Solid-State Circuits, 45(11), 2356–2365.Google Scholar
  15. 15.
    Rieger, R. (2011). Variable-gain, low-noise amplification for sampling front ends. IEEE Transactions on Biomedical Circuits and Systems, 5(3), 253–261.CrossRefMathSciNetGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  • Fernando Rangel de Sousa
    • 1
  • Roddy Alexander Romero Antayhua
    • 1
  1. 1.Radio Frequency Laboratory, Department of Electrical and Electronic Engineering Federal University of Santa Catarina (UFSC)FlorianópolisBrazil

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